Air filter



FIG. 1 is a perspective view showing the new design for an air filter.

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a side view thereof;

FIG. 6 is a perspective view showing the new design for an air filter;

FIG. 7 is an enlarged view of a portion of the air filter of FIG. 6;

FIG. 8 is a top thereof; and,

FIG. 9 is an enlarged view of a portion of the air filter of FIG. 8.

The claimed area of the air filter is illustrated with the color designation for the color yellow. The thicker dash-dash broken lines define the boundaries of the claimed design and form no part thereof.

The portions in the drawing views shown in broken lines form no part of the claimed design. 

CLAIM The ornamental design for an air filter, as shown and described. 